U.S. patent number 6,061,561 [Application Number 08/731,289] was granted by the patent office on 2000-05-09 for cellular communication system providing cell transmitter location information.
This patent grant is currently assigned to Nokia Mobile Phones Limited. Invention is credited to Seppo Alanara, Mika Pekka Antero Tarkiainen.
United States Patent |
6,061,561 |
Alanara , et al. |
May 9, 2000 |
Cellular communication system providing cell transmitter location
information
Abstract
Methods and apparatus are disclosed for operating a cellular
communication network. An exemplary method includes the steps of
transmitting a message from a base station (30) to a mobile station
(10) located within a cell served by the base station, the message
including location information for specifying a geographical
location of the base station; storing the location information in
the mobile station; originating a predetermined call type with the
mobile station and appending the stored location information to a
call origination message; and routing the call from the network to
the call's destination in conjunction with the appended location
information. The location information includes at least one of a
latitude and a longitude at which the base station is located and
an alphanumeric string that is expressive of a geographical
location at which the base station is located. The base station
location information is useful in determining a location of the
mobile station, such as when an emergency call is made. In a
further embodiment of this invention an emergency call is
originated by a mobile station in response to the deployment of an
air bag in a vehicle wherein the mobile station is located.
Inventors: |
Alanara; Seppo (Oulu,
FI), Tarkiainen; Mika Pekka Antero (Oulu,
FI) |
Assignee: |
Nokia Mobile Phones Limited
(Salo, FI)
|
Family
ID: |
24938882 |
Appl.
No.: |
08/731,289 |
Filed: |
October 11, 1996 |
Current U.S.
Class: |
455/456.1;
455/517; 455/457 |
Current CPC
Class: |
G01S
19/17 (20130101); H04W 4/90 (20180201); H04W
76/50 (20180201); G01S 5/0027 (20130101); G01S
2205/008 (20130101); G01S 2205/006 (20130101) |
Current International
Class: |
G01S
5/14 (20060101); H04Q 7/38 (20060101); G01S
5/00 (20060101); G01S 003/02 () |
Field of
Search: |
;455/456,457,517,422
;342/450 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rao; Anand S.
Attorney, Agent or Firm: Ohlandt, Greeley, Ruggiero &
Perle, L.L.P
Claims
What is claimed is:
1. A method for operating a cellular communication network,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a cell served by the base station, the
message comprising location information for specifying a
geographical location of the base station;
storing the location information in the mobile station;
originating a predetermined call type with the mobile station and
appending the stored location information to a call origination
message; and
routing the call from the network to the call's destination in
conjunction with the appended location information;
wherein the location information is comprised of an alphanumeric
string that is descriptive of a name of a place where the base
station is installed; and further comprising a step of
displaying at least a portion of the stored alphanumeric string to
a user of the mobile station.
2. A method as set forth in claim 1, wherein the location
information further comprises a latitude and a longitude at which
the base station is located.
3. A method for operating a cellular communication network,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a cell served by the base station, the
message comprising location information for specifying a
geographical location of the base station;
storing the location information in the mobile station;
originating a call with the mobile station;
routing the call from the network to the call's destination;
at the call's destination, originating a message to the mobile
station to interrogate the mobile station for the stored location
information; and
in response to receiving the interrogation message at the mobile
station, transmitting a message that includes the stored location
information;
wherein the location information comprises an alphanumeric string
that is descriptive of a name of a place where the base station is
installed; and further comprising a step of
displaying at least a portion of the stored alphanumeric string to
a user of the mobile station.
4. A method as set forth in claim 3, wherein the location
information further comprises a latitude and a longitude at which
the base station is located.
5. A method for operating a cellular communication network,
comprising the steps of:
originating a predetermined call type with a mobile station;
detecting at a base station that serves a cell within which the
mobile station is located that the mobile station has originated
the predetermined call type;
and
in response to detecting the predetermined call type, routing the
call from the base station to the call's destination while
appending location information to the routed call for specifying a
geographical location of the base station, the location information
being appended to the routed call external to the mobile station
and prior to the call's arrival at the call's destination.
6. A method as set forth in claim 5, wherein the location
information includes a latitude and a longitude at which the base
station is located.
7. A method as set forth in claim 5, wherein the location
information includes an alphanumeric string that is expressive of a
geographical location at which the base station is located.
8. A method for operating a cellular communication network,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a cell served by the base station, the
message including location information for specifying a
geographical location of the base station;
determining a current geographical location of the mobile
station;
calculating a distance to the base station from the mobile station
in accordance with the determined current location of the mobile
station and in accordance with the location information received
from the base station;
calculating time alignment information in the mobile station for
adjusting an arrival time of a burst, transmitted by an RF
transmitter of the mobile station, at the base station's receiver,
wherein the time alignment information is calculated in accordance
with the calculated distance; and
setting the mobile station's transmitted burst timing in accordance
with the calculated time alignment information so as to reduce a
probability that the transmitted burst will arrive at the base
station's receiver during a time that a transmitted burst from
another mobile station arrives at the base station's receiver.
9. A method as set forth in claim 8, and further comprising the
step of:
determining in the mobile station whether to transmit a normal
length burst or a shortened burst in accordance with the calculated
distance to the base station.
10. A method for operating a cellular communication network,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a cell served by the base station, the
message including location information for specifying a
geographical location of the base station;
determining a current geographical location of the mobile
station;
calculating a distance to the base station from the mobile station
in accordance with the determined current location of the mobile
station and in accordance with the location information received
from the base station; and
determining in the mobile station whether to transmit a normal
length burst or a shortened burst in accordance with the calculated
distance to the base station.
11. A method as set forth in claim 10, and further comprising the
steps of:
calculating time alignment information in the mobile station for
adjusting an arrival time of a burst, transmitted by the mobile
station, at the base station's receiver; and
setting the mobile station's transmitted burst timing in accordance
with the calculated time alignment information.
12. A cellular communication system having at least one base
station that serves at least one mobile station that is located
within a cell defining a service area of the base station, said
system comprising:
a first memory for storing location information for specifying a
geographical location of the base station;
means for transmitting a wireless message to said mobile station,
the message including said location information; and
a second memory in said mobile station for storing said location
information that is received from said base station;
wherein the location information is comprised of an alphanumeric
string that is descriptive of a name of a place where the base
station is installed; and further comprising
a display for displaying at least a portion of the stored
alphanumeric string to a user of the mobile station.
13. A system as set forth in claim 12, wherein said mobile station
further comprises means for originating a predetermined call type
and for appending the stored location information to a call
origination message for the predetermined call type, and wherein
said system includes means for routing the call to the call's
destination in conjunction with the
appended location information.
14. A system as set forth in claim 12, wherein said mobile station
further comprises means for originating a telephone call, wherein
said system includes means for routing the telephone call to the
call's destination, and wherein said mobile station is responsive
to a received interrogation message for transmitting a message that
includes the stored location information.
15. A system as set forth in claim 12, wherein said mobile station
further comprises:
means for determining a current geographical location of the mobile
station;
means for calculating a distance to the base station from the
mobile station in accordance with the determined current location
of the mobile station and in accordance with the location
information received from the base station; and
means for calculating time alignment information for adjusting an
arrival time of a burst, transmitted by the mobile station, at the
base station's receiver and for setting the mobile station's
transmitted burst timing in accordance with the calculated time
alignment information.
16. A system as set forth in claim 12, wherein said mobile station
further comprises:
means for determining a current geographical location of the mobile
station;
means for calculating a distance to the base station from the
mobile station in accordance with the determined current location
of the mobile station and in accordance with the location
information received from the base station; and
means for determining whether to transmit a normal length burst or
a shortened burst in accordance with the calculated distance to the
base station.
17. A system as set forth in claim 12, wherein the location
information is further comprised of a latitude and a longitude at
which the base station is located.
18. A cellular communication system having at least one base
station that serves at least one mobile station that is located
within a cell defining a service area of the base station, said
system comprising:
a memory, disposed external to said mobile station, for storing
location information for specifying a geographical location of the
base station;
said mobile station comprises means for originating a predetermined
call type and for transmitting a call origination message to the
base station; and wherein said system further comprises means,
coupled to said memory, for routing the call to the call's
destination in conjunction with appended base station location
information that is retrieved from said memory, the base station
location information being appended to the routed call external to
the mobile station and prior to the call's arrival at the call's
destination.
19. A system as set forth in claim 18, wherein the location
information includes at least one of a latitude and a longitude at
which the base station is located or an alphanumeric string that is
expressive of the geographical location at which the base station
is located.
20. A mobile station operable with a base station for conducting
bidirectional wireless communication, said mobile station
comprising:
means for determining a current geographical location of the mobile
station;
means for calculating a distance to the base station from the
mobile station in accordance with the determined current location
of the mobile station and in accordance with location information
received from the base station, the location information specifying
a geographical location of the base station; and
means for calculating time alignment information for adjusting an
arrival time of a burst, transmitted by the mobile station, at the
base station's receiver and for setting the mobile station's
transmitted burst timing in accordance with the calculated time
alignment information, wherein the time alignment information is
calculated in accordance with the calculated distance.
21. A mobile station operable with a base station for conducting
bidirectional wireless communication, said mobile station
comprising:
means for determining a current geographical location of the mobile
station;
means for calculating a distance to the base station from the
mobile station in accordance with the determined current location
of the mobile station and in accordance with location information
received from the base station, the location information specifying
a geographical location of the base station; and
means for determining whether to transmit a normal length burst or
a shortened burst in accordance with the calculated distance to the
base station.
22. A method for operating a cellular communication system,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a cell served by the base station, the
message including location information for specifying a
geographical location of the base station;
determining a current geographical location of the mobile
station;
calculating a distance to the base station from the mobile station
in accordance with the determined current location of the mobile
station and in accordance with the location information received
from the base station; and
determining, in the mobile station and in accordance with the
calculated distance, at least one timing related characteristic or
power related characteristic of a signal to be transmitted by the
mobile station to the base station.
23. A method as set forth in claim 22, wherein the characteristic
includes at least one of a time alignment of a burst, a length of a
burst, and a power level at which the mobile station transmits the
burst.
24. A method for operating a cellular communication system,
comprising the steps of:
transmitting a wireless message from a base station to a mobile
station located within a vehicle, the vehicle being disposed within
a cell served by the base station, the message including location
information for specifying a geographical location of the base
station, the location information comprising an alphanumeric string
that is descriptive of a name of a place where the base station is
installed;
storing the location information within a memory device of the
mobile station; and
in response to an activation of a passenger safety system of the
vehicle, originating an emergency call from the mobile station, the
emergency call including the stored location information.
25. A method as set forth in claim 24, wherein the passenger safety
system includes an air bag system.
26. A method as set forth in claim 24, wherein the step of
originating includes the steps of:
determining a current position of the vehicle from a vehicular
navigation system; and
including the determined current position with the stored location
information.
27. A method as set forth in claim 24, and further comprising a
step of including other information with the stored location
information, the other information being descriptive of a user of
the mobile station.
28. A method as set forth in claim 27, wherein the other
information is also stored in the memory of the mobile station.
29. A method for operating a non-public cellular communication
system of a type that comprises a plurality of microcells each
serviced by a local base station, comprising the steps of:
transmitting a message from a first one of the local base stations
to a mobile station located within a first microcell serviced by
the first one of the local base stations, the message comprising a
first alphanumeric string that is descriptive of a name of an area
serviced by the first one of the local base stations;
receiving the message and storing the first alphanumeric string in
a memory of the mobile station;
displaying at least a portion of the first alphanumeric string to a
user of the mobile station;
in response to the mobile station moving from the first microcell
to a second microcell, transmitting a message to the mobile station
from a second one of the local base stations that services the
second microcell, the message comprising a second alphanumeric
string that is descriptive of a name of an area serviced by the
second one of the local base stations;
receiving the message and storing the second alphanumeric string in
the memory of the mobile station; and
displaying at least a portion of the second alphanumeric string to
the user of the mobile station.
30. A method as in claim 29, wherein the step of storing the second
alphanumeric string includes a step of over-writing the first
alphanumeric string.
Description
FIELD OF THE INVENTION
This invention relates generally to cellular communication systems
and to subscriber mobile stations that operate within such
systems.
BACKGROUND OF THE INVENTION
Cellular communication systems, such as those providing cellular
telephone and personal communicator service, are characterized by
overlapping cells each having a cell site transmitter. The cell
site transmitters are often referred to as base stations. Such
cellular communication systems include public systems that serve a
city or region, residential systems that serve a home or office,
and private systems that serve, by example, an office building or a
hotel. The cells of the latter two systems are typically much
smaller than the cells of the public system, which may have a
diameter of several kilometers. A typical mobile station or user
transceiver terminal is capable of movement between adjacent cells,
with an ongoing communication connection being handed off between
base stations as the mobile station leaves the coverage area of one
cell and enters the coverage area of another cell.
While in most instances the exact geographical location of the base
stations or mobile stations is of little importance, it can be
appreciated that in certain situations, such as emergency
situations, this information may become very important. By example,
if a user were to place an emergency call (e.g., a 911 call), then
an ability to accurately determine the location of the user can aid
in dispatching emergency services to the user. This is especially
true when calls are received from highway travelers who may be
unfamiliar with the region from where they are making the emergency
call, and who may thus be unable to give their location.
Furthermore, in some circumstances the user may be physically
incapable of communicating their location when placing an emergency
call. Unfortunately, many conventional cellular communication
systems do not provide a mechanism to determine and report the
user's location with a degree of specificity that would aid in
rapidly locating the user.
Another useful feature that is not adequately addressed by
conventional cellular communication systems is an ability to inform
a mobile station user of an approximate location of the user
relative to a geographical area within which a base station is
situated. For example, it would be useful to indicate, especially
at night or in inclement weather, that the user is passing through
or close to a certain town, or is located near to a major highway
intersection. Currently specified cellular communication systems do
not address this need.
OBJECTS OF THE INVENTION
It is thus a first object of this invention to provide an improved
cellular communication system that overcomes the foregoing and
other problems.
It is a second object of this invention to provide a cellular
communication system wherein a base station is enabled to
communicate its geographical location to a mobile station.
It is a further object of this invention to provide a cellular
communication system wherein a base station is enabled to
communicate its geographical location to a party called by the
mobile station.
It is another object of this invention to provide a cellular
communication system wherein a mobile station and/or base station
is enabled to accurately determine a distance between the base
station and the mobile station, thereby enabling accurate time
alignment, burst length, power settings, and other functions to be
implemented based on the determined distance between the base
station and the mobile station.
It is one further object of this invention to provide a cellular
communications systems wherein a vehicular mobile station is
enabled to automatically place an emergency call in response to a
triggering incident, such as the deployment of an air bag during a
collision.
SUMMARY OF THE INVENTION
The foregoing and other problems are overcome and the objects of
the invention are realized by methods and apparatus in accordance
with embodiments of this invention.
A method is disclosed for operating a cellular communication
network, comprising the steps of transmitting a message from a base
station to a mobile station located within a cell served by the
base station, the message including location information for
specifying a geographical location of the base station; storing the
location information in the mobile station; originating a
predetermined call type with the mobile station and appending the
stored location information to a call origination message; and
routing the call from the network to the call's destination in
conjunction with the appended location information.
The location information includes at least one of a latitude and a
longitude at which the base station is located and an alphanumeric
string that is expressive of a geographical location at which the
base station is located.
In accordance with another method for operating a cellular
communication network there is disclosed the steps of transmitting
a message from a base station to a mobile station located within a
cell served by the base station, the message including location
information for specifying a geographical location of the base
station; storing the location information in the mobile station;
originating a call with the mobile station; routing the call from
the network to the call's destination; at the call's destination,
originating a message to the mobile station to interrogate the
mobile station for the stored location information; and in response
to receiving the interrogation message at the mobile station,
transmitting a message that includes the stored location
information.
In accordance with a further method for operating a cellular
communication network there is disclosed the steps of originating a
predetermined call type with the mobile station; detecting at a
base station that serves a
cell within which the mobile station is located that the mobile
station has originated the predetermined call type; and in response
to detecting the predetermined call type, routing the call from the
base station to the call's destination while appending location
information to the routed call for specifying a geographical
location of the base station.
In accordance with a still further method for operating a cellular
communication network there is disclosed the steps of transmitting
a message from a base station to a mobile station located within a
cell served by the base station, the message including location
information for specifying a geographical location of the base
station; determining a current geographical location of the mobile
station; calculating a distance to the base station from the mobile
station in accordance with the determined current location of the
mobile station and in accordance with the location information
received from the base station; calculating time alignment
information in the mobile station for adjusting an arrival time of
a burst, transmitted by the mobile station, at the base station's
receiver; and setting the mobile station's transmitted burst timing
in accordance with the calculated time alignment information.
In this method the mobile station may also determine instead of, or
in conjunction with, the time alignment information whether to
transmit a normal length burst or a shortened burst in accordance
with the calculated distance to the base station.
In a further embodiment of this invention there is disclosed a
method for operating a cellular communication system, the method
including the steps of (a) transmitting a message from a base
station to a mobile station located within a vehicle, the vehicle
being disposed within a cell served by the base station, the
message including location information for specifying a
geographical location of the base station; (b) storing the location
information within a memory device of the mobile station; and (c)
in response to an activation of a passenger safety system of the
vehicle, such as an air bag system, originating an emergency call
from the mobile station, the emergency call including the stored
location information. The step of originating includes the steps of
determining a current position of the vehicle from a vehicular
navigation system; and including the determined current position
with the stored location information. A further step of the method
includes other information with the stored location information in
the originated emergency call, the other information being
descriptive of a user of the mobile station, such as the user's
name, social security number, blood type, etc. In this embodiment
the other information is also stored in the memory device of the
mobile station.
BRIEF DESCRIPTION OF THE DRAWINGS
The above set forth and other features of the invention are made
more apparent in the ensuing Detailed Description of the Invention
when read in conjunction with the attached Drawings, wherein:
FIG. 1 is a block diagram of a mobile terminal that is constructed
and operated in accordance with this invention;
FIG. 2 is an elevational view of the mobile terminal shown in FIG.
1, and which further illustrates a cellular communication system to
which the mobile terminal is bidirectionally coupled through
wireless RF links;
FIGS. 3-6 illustrate various exemplary message formats for
communicating base station location information to the mobile
station;
FIGS. 7, 8 and 9 are logic flow diagrams that illustrate methods of
this invention; and
FIG. 10 is a block diagram of an embodiment of this invention
wherein a cellular telephone carried within a vehicle is coupled to
a vehicle air bag deployment system for automatically originating
an emergency call in response to a deployment of an air bag, the
emergency call including vehicle location information.
DETAILED DESCRIPTION OF THE INVENTION
Reference is made to FIGS. 1 and 2 for illustrating a wireless user
or mobile station 10 such as, but not limited to, a cellular
radiotelephone or a personal communicator, that is suitable for
practicing this invention. The mobile station 10 includes an
antenna 12 for transmitting signals to and for receiving signals
from a base site or base station 30. The base station 30 is a part
of a cellular network comprising a Base Station/Mobile Switching
Center (MSC)/and Internetworking Function, or BMI 32, that includes
a Mobile Switching Center (MSC) 34. The MSC 34 provides a
connection to landline trunks when the mobile station 10 is
involved in a call.
The mobile station includes a modulator (MOD) 14A, a transmitter
14, a receiver 16, a demodulator (DEMOD) 16A, and a controller 18
that provides signals to and receives signals from the transmitter
14 and receiver 16, respectively. These signals include signaling
information in accordance with the air interface standard of the
applicable cellular system, and also user speech and/or user
generated data. The air interface standard is assumed for this
invention to include a Time Division Multiple Access (TDMA)
physical and logical frame structure of a type that is specified in
IS-136.1 and IS-136.2, Rev. A, although the teaching of this
invention is not intended to be limited only to this specific
structure, or for use only with a digital IS-136 compatible mobile
station, or for use only in TDMA type systems.
A user interface includes a conventional earphone or speaker 17, a
conventional microphone 19, a display 20, and a user input device,
typically a keypad 22, all of which are coupled to the controller
18. The keypad 22 includes the conventional numeric (0-9) and
related keys (#,*) 22a, and other keys 22b used for operating the
mobile station 10. These other keys 22b may include, by example, a
SEND key, various menu scrolling and soft keys, and a PWR key. The
mobile station 10 also includes a battery 26 for powering the
various circuits that are required to operate the station.
The mobile station 10 also includes various memories, shown
collectively as the memory 24, wherein are stored a plurality of
constants and variables that are used by the controller 18 during
the operation of the mobile station. For example, the memory 24
stores the values of various cellular system parameters and the
number assignment module (NAM). An operating program for
controlling the operation of controller 18 is also stored in the
memory 24 (typically in a ROM device). The memory 24 may also store
data, including user messages, that is received from the BMI 32
prior to the display of the messages to the user.
It should be understood that the mobile station 10 can be a vehicle
mounted or a handheld device. It should further be appreciated that
the mobile station 10 can be capable of operating with one or more
air interface standards, modulation types, and access types. By
example, the mobile station may be capable of operating with any of
a number of other standards besides IS-136, such as GSM and IS-95
(CDMA). Narrow-band AMPS (NAMPS), as well as TACS, mobile stations
may also benefit from the teaching of this invention. It should
thus be clear that the teaching of this invention is not to be
construed to be limited to any one particular type of mobile
station or air interface standard.
The operating program in the memory 24 includes routines to present
messages and message-related functions to the user on the display
20. The memory 24 also includes routines for implementing the
methods described below in relation to FIGS. 7-9. The BMI 32 is
assumed to include a controller and memory for implementing the BMI
portion of these methods.
In accordance with this invention the BMI 32 includes a memory 31
for storing information expressive of a geographical location of
the base station 30. In a preferred embodiment of this invention
the location is stored as latitude (degrees, minutes, seconds),
longitude (degrees, minutes, seconds), and as an alphanumeric
string, e.g., "Smalltown, Texas", "Southwest Dallas", "Empire State
Building, Midtown Manhattan", "Intersection I-495 and Route 202",
etc. When used in a private cellular network the alphanumeric
string may convey a name and location of the private system
provider, such as a name of a hotel or corporation. Microcells
within the private (or residential) systems can also be separately
identified, e.g., "Hotel Name, Floor 12".
In other embodiments of the invention only the latitude and
longitude may be used, or only the alphanumeric string may be used.
The location information can be programmed into the memory 31 at
the time the base station 30 is installed or placed into service.
The latitude and longitude is typically accurately known a priori,
or can be determined by well-known surveying or satellite location
techniques. By "accurately known", it is assumed for the purposes
of this invention that the location is known to a precision that is
suitable for distinguishing the location from the locations of
other base stations. In a preferred embodiment of this invention
the location information is expressed with a resolution given in
degrees, minutes, and seconds of latitude and longitude. In other
embodiments the location could be expressed in, by example, tenths
or hundredths of a second resolution.
In a preferred embodiment of this invention the air interface
standard (i.e., IS-136) includes a System Identity message
(IS-136.1, Rev. A, Section 6.4.1.1.1.5). As is illustrated in FIG.
3, the System Identity message is modified to include an 80 byte
Alphanumeric Location Name field and a 38 byte Geographical
Location field. The format of the Geographical Location field is
illustrated in FIG. 4, the format of the Longitude, E/W sub-field
is illustrated in FIG. 5, and the format of the Latitude, S/N
sub-field is illustrated in FIG. 6. It should be noted that the
value of the Longitude, degrees sub-field is 0-180 degrees, and the
Longitude, E/W field is used as a sign. It should be further noted
that the value of the Latitude, degrees sub-field is 0-90 degrees,
and the Latitude, S/N field is used as a sign.
The base station 30 is enabled to transmit the stored location
information as part of the System Identity message to mobile
stations 10 that are within the cell serviced by the base station
30. Referring also to FIG. 1, the mobile station 10 stores the
received location information in a Read/Write portion of the memory
24 in predetermined latitude (LAT), longitude (LONG), and
alphanumeric string (A-STR) locations. When the mobile station 10
is handed off to another base station 30, the new base station's
location information is preferably written over the location
information of the previous base station. When monitoring several
base stations to determine a best base station to service the
mobile station, the mobile station 10 may employ multiple memory
locations for storing location information received from each of
the monitored base stations.
In accordance with this invention new information elements are thus
added to the Digital Control Channel (DCCH) broadcast information.
The new information elements specify the geographical location of
the cell transmitter. The geographical location is identified with
at least one of an alphanumeric string (name of city, town, suburb,
village, etc.) and a binary coded location in degrees (latitude
deg:min:sec N/S, longitude deg:min:sec E/W).
In one aspect of this invention the location information may be
interrogated by a 911 operator from the mobile station 10, using a
request message that forms a part of the Short Message Service
(SMS)/Paging Channel (PCH)/Access Response Channel (ARCH), or SPACH
message set of IS-136.1. Upon a receipt of this request message the
controller 18 of the mobile station 10 accesses the memory 24 and
transmits the stored base station location information to the 911
operator.
In another aspect of this invention the stored location
information, such as the alphanumeric information, is displayed to
the user on the display 20. In this manner the user is enabled to
read the location information to the 911 operator, thereby
indicating an approximate location of the user. By viewing the
displayed location information the user can thus determine the
location of the cell where the mobile phone is being serviced.
Usually in urban areas the cell size is small, and thus the user
enabled to provide fairly accurate location information in cases of
emergency.
The location information of the serving cell can also be used to
verify that the mobile station 10 stays on the best available cell,
which is typically the cell having a base station 30 that is
nearest to the mobile station 10. If the mobile station 10 is also
equipped with or connected to a satellite location system, the
mobile station 10 can then calculate, using conventional
techniques, a distance to the base station 30 of the serving cell.
The calculated distance information can be used, either alone or in
conjunction with received signal strength (RSS) information, to
calculate, in the mobile station 10, an accurate time alignment
value. The calculated time alignment value can then be used when
making a DCCH random access. A mobile station 10 using RACH time
alignment may thus also use a normal length RACH burst when in a
cell that uses an abbreviated burst length.
Further in this regard, reference can be made to Section 2.1.3.3.5
of IS-136.2, Rev. A. In general, time alignment is a process of
controlling the time of TDMA time slot burst transmissions from the
mobile station 10 by advancing or retarding the mobile station
transmit burst so that it arrives at the base station receiver in
the proper time relationship to other time slot burst
transmissions. An error in time alignment is caused by the arrival
of power from two different mobile station transmitters
simultaneously at the base station receiver. This in turn causes
errors in both signals. The overlap in transmission occurs at the
beginning or end of a time slot. Upon detecting an overlap
condition, the base station 32 sends an appropriate Physical Layer
Control message containing a time alignment information element to
the mobile station 10 using the appropriate forward signaling
channel.
In IS-136, the format of the Physical Layer Control message is
described in Section 3.7.3.1.3.2.5. The time adjustment parameter
in that message provides for advancing or retarding the time of the
mobile station transmit burst in units of 1/2 symbols. Upon receipt
of a Physical Layer Control message containing a time alignment
information element, the mobile station 10 change its timing in one
adjustment.
At certain times it may be necessary for a mobile station 10, while
operating on a digital traffic channel, to transmit a shortened
burst during its slot interval (see Section 2.1.3.3.5.4), so as to
avoid collisions at the base station 30 between the mobile
station's burst slot and the burst of a neighboring slot. This
collision of neighboring bursts at the base station is due to the
mobile station not having the proper time alignment information
corresponding to its distance from the base station.
Estimated time alignment information is also used when handing off
the mobile station 10 from one digital traffic channel to another.
For smaller diameter cells, the estimated time alignment
information is used to adjust the transmit timing of the mobile
station 10 so that there are be no burst collisions at the base
station 30. For systems with sector to sector handoff, the
estimated time alignment information is also used to adjust the
mobile station transmit timing so that there are no burst
collisions at the base station 30. For larger diameter cells,
however, the estimated time alignment information may not be
accurate enough to avoid burst collisions at the base station
30.
In accordance with an aspect of this invention, and assuming that
the mobile station 10 is enabled to determine its location, such as
from a global positioning system (GPS) satellite location subsystem
36 (see FIG. 1), the mobile station 10 is enabled to accurately
determine the distance between the mobile station's transmitter
antenna 12 and the base station's receive antenna 30b (FIG. 2). The
mobile station 10 is then enabled to calculate, using a technique
that is similar or identical to techniques known for the base site
equipment, accurate time alignment information, as opposed to
receiving time alignment information from the base station 30. In
this manner the mobile station 10 is enabled to avoid collisions
with bursts transmitted by other mobile stations. The use of
unnecessary shortened bursts may also be eliminated, thereby
increasing the amount of information that can be transmitted to the
base station 30 in one burst. This makes more efficient use of the
random access channel, in that a
conventional two or more shortened burst transmission may be made,
when possible, in fewer bursts.
The calculated distance information can also be used by the mobile
station 10 when determining an initial power level with which to
transmit an access request, in that generally less transmitter
power is required when the mobile station 10 is nearer to the base
station 30. Such power calculations may also be of benefit for CDMA
mobile stations, such as those specified by IS-95, wherein an
equalization of received powers at the base station, for mobile
stations sharing the spectrum, is an important consideration.
Reference is now made to FIGS. 7, 8 and 9 for illustrating three
further methods in accordance with the teaching of this
invention.
In FIG. 7, at Block A, the BMI 32 transmits the base station
location information to the mobile station 10. At Block B the
mobile station 10 stores the location information in memory 24. At
Block C the mobile station 10 originates a predetermined call type
(e.g., a 911 call) and appends the stored location information to
the call origination message. At Block D the call is routed by the
BMI 32 to the call's destination (e.g., a 911 operator) along with
the appended location information. The receiving party is thus
enabled to automatically determine that the mobile station 10 is
located within a cell served by the base station 30, and thus has
an indication of the geographical location of the user.
This method can be modified as described above such that the
receiving party uses a message to interrogate the mobile station 10
for the location information, after which the mobile station 10
transmits the location information using an appropriate response
message.
In accordance with another method of this invention, and referring
to FIG. 8, at Block A the mobile station 10 originates the
predetermined call type (e.g., a 911 call). At Block B the BMI 32
recognizes that the mobile station 10 has originated the
predetermined call type. At Block C the BMI 32 accesses the memory
31 and appends the location of the serving base station 30 to the
call and routes the call to the destination. As in the method of
FIG. 7, the receiving party is thus enabled to automatically
determine that the mobile station 10 is located within a cell
served by the base station 30.
In accordance with a further method of this invention, and
referring to FIG. 9, at Block A the BMI 32 transmits the location
information to the mobile station 10. At Block B the mobile station
10 uses the location information to calculate the distance to the
base station 30 in accordance with a current location of the mobile
station 10. The mobile station's location can be determined by, for
example, the satellite location system 36, or any other suitable
position determining means. Based on the calculated distance the
mobile station 10 then calculates the time alignment information
required to adjust the arrival time of the mobile station's
transmitted burst at the base station's receiver. At Block C the
mobile station 10 sets its transmitted burst in accordance with the
calculated time alignment information. At Block D the mobile
station 10 may optionally determine whether to transmit a normal
length burst or a shortened burst in accordance with the calculated
distance to the base station 30. It is also within the scope of the
invention to use the calculated distance to first make the normal
length/shortened burst determination, and then optionally perform
the time alignment process.
Although described in the context of preferred embodiments, it
should be realized that a number of modifications to these
teachings may occur to one skilled in the art. By example, the
latitude and longitude can be expressed with any degree of
precision, and is not limited for expression in only a
degree:minute:second format. Furthermore, for the case where the
mobile station 10 includes the satellite location system, the
mobile station 10 is enabled to transmit its own location when
originating a call or in response to being interrogated by another
party, and need not transmit any location information received from
the base station 30.
FIG. 10 is a block diagram of a further embodiment of this
invention wherein the cellular telephone mobile station 10 carried
within a vehicle is coupled to a vehicle air bag system 38 for
automatically originating an emergency call in response to a
deployment of an air bag, wherein the emergency call includes at
least a location of the vehicle.
More particularly, the vehicle includes the air bag controller 40
having an input connected to a collision sensor 42. In response to
a signal from the sensor 42 the controller 40 generates an air bag
activate signal 44. The activate signal 44 is connected to an air
bag deployment system 46 which responds to the activate signal by
inflating, i.e., deploying, one or more air bags within the
passenger compartment of the vehicle.
In accordance with this embodiment of the invention the same or a
different activate signal is coupled over a link 44a to the
controller 18 of the mobile station 10. The link 44a may be a wired
link, an infrared link, a low power RF link, or any suitable
mechanism for coupling the controller 18 to the output of the air
bag controller 44. In any case, the controller 18 becomes aware of
the deployment of the vehicle's air bag(s) during a collision. In
response to the activate signal being asserted, the controller 18
automatically originates an emergency or distress call to an
emergency center, such as a 911 center, via the transmitter 14 and
antenna 12. Further in accordance with this invention, the
emergency call includes position information for locating the
vehicle, and may also include other information that is programmed
into the memory 24, such as a name, social security number, blood
type, primary physician, etc., of a user of the mobile station
10.
In one embodiment the position information is obtained, as
described above, from the location information that is transmitted
from the base station 30 and stored in the memory 24 of the mobile
station (see FIG. 7). In a further embodiment of this invention the
base station 30 may append the location information to the
originated emergency call (see FIG. 8). In a still further
embodiment of this invention the satellite location system 36 of
FIG. 1 is also interrogated by the controller to determine a
current or last position of the vehicle, and this position
information is appended to the emergency call by the controller 18,
along with the stored base station location information. In this
latter embodiment the vehicle includes a vehicle navigation system
48 having a Global Positioning System (GPS) satellite receiver 52
that receives, via antenna 54, transmissions from one or more GPS
satellites 56. The vehicle navigation system 48 may further include
an inertial, dead reckoning, or other type of navigation system for
maintaining a current position of the vehicle, wherein the GPS
position information is employed for periodically updating the
vehicle's position. Alternatively, the GPS receiver 52 may be the
vehicle's primary navigation information system.
Although described specifically in the context of an air bag
deployment system, it can be appreciated that this embodiment of
the invention can originate an emergency call in response to a
signal from any type of vehicle passenger safety system. By
example, if the vehicle is equipped with a smoke, heat, or flame
sensor, the output of the sensor can be coupled to the controller
18 for initiating the origination of the emergency call.
Thus, while the invention has been particularly shown and described
with respect to preferred embodiments thereof, it will be
understood by those skilled in the art that changes in form and
details may be made therein without departing from the scope and
spirit of the invention.
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